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    <title>Document</title>
    <script>

        //算数运算

        var num1 = 10;
        var num2 = 20;
        var num3 = 3;

        console.log("num1 :",num1);
        console.log("num2 :",num2);
        console.log("num3 :",num3);
        


        console.log("num1 + num2 :",num1 + num2);  //30
        console.log("num1 - num2 :",num1 - num2);  // -10
        console.log("num1 * num2 :",num1 * num2);  // 200
        console.log("num1 / num2 :",num1 / num2);  // 0.5
        console.log("num1 % num3 :",num1 % num3);  // 1

        // num1++

        // num1 = num1 + 1 ;
        // num1++;
        ++num1;
       
        console.log("num1 ",num1);
        
        var num4 = 5;
        // var  result =   (num4++) * 2;  
        var  result =   (++num4) * 2;  

        console.log("result ",result);
        console.log("num4 ",num4);

    
        // num1 = num1 - 1 ; 
        // num1--;








        

   </script>
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